I've always lived in solitude but I never let this fact destroy my personality. It had its advantages as well as drawbacks but I struggled to take the maximum benefit from it. Sometimes being alone is better than being surrounded by morons, don't you say? After all, they say that silence is gold and solitude just offers it to you.
I suffered from depression various times but I always overcame it somehow without becoming a bad person. The "I don't care" thingy doesn't work out because you cannot deny your feelings. If people offend you repeatedly, you can say "I don't care at all" but do you really not care from inside? No, I bet. You feel down about it so you eventually fall into depression. However, before doing so, be sure that you are not surrounded by cretins, otherwise your depression would be based on the words of mindless people. If that's not the case, haven't you thought that you could be the problem in the first place? Are you too introvert, shy, aggressive, anti-social? Judge yourself before judging others and see if there's something wrong with you. Nobody will hate someone for no reason. This is how I dealt with my own problems of solitude and depression successfully.